Electromagnetic apparatus



Feb. 18, 1936. .1. BETHENOD ET'AL 7 ELECTROMAGNETIC APPARATUS Filed Dec.29, 1933 ATTOR/YEX v f Patented Feb. 18, 1936 ELECTROMAGNETIC APPARATUSJoseph Bethenod, Paris, and Andre Claude, Nanterre, France, assignors toSocit Anonyme pour les Applications de lElectricite & des Gaz HaresEtablissements Claude-Paz & Silva,

a corporation oi France Applicatiollin December 29, 1933, Serial No.704,558

Germany January 9, 1933 The capital importance of a considerable currentdensity for the production of ultra-violet and luminous radiations ofadjustable composition has already been pointed out in the prior U. S.A. patent application No. 618,402, filed June V 20, 1932. When raregases, such as krypton and xenon, are acted upon by electro-magneticinduction, this considerable density is obviously an increasing functionof the rate of variation of the magnetic field in each point of theenvelope. According to the present invention, the necessary rate forvariation may be attained with currents of a frequency not exceedingthat which may be produced industrially by an alternator, say about30,000 cycles per second, provided that conditions are so arranged toobtain a magnetic field of sufficient amplitude.

At any rate, the invention will be well understood with the aid of theaccompanying drawing, wherein Figures 1 and 2 are diagrammatic. viewsshowing arrangements of the type under consideration.

In Figure 1, the spherical vessel I is shown provided with a cylindricalcasing 2 which penetrates into the interior and forms a gas-tighthousing for a coil 3, the terminals 4 of which are connected to a sourceof high-frequency current,

such as an alternator, a triode generator or the like. Experiment showsthat the desired efiectis thus obtained under excellent conditions.According to one of the features of the invention, these conditions arestill further improved by disposing within the coil 3, a core 5 ofmagnetic substance, formed for example of strips of thin sheet iron(placed radially) or by wires of very small diameter, with a view toreducing, in known manner, the eddy current losses. point of view, it isof advantage to make the said magnetic core of metal in the state ofpowder,

the grains of which are agglomerated by a suit- Experiment shows ableinsulating substance. that it is thus possible to attain, even atfrequencies of the order of those employed in radiotelegraphy, anapparent permeability of at least '7 to 8 (the permeability of air beingtaken as unity), the losses remaining well within the acceptable limits.

In Figure 2, the inductance coil 3 is wound outside the vessel l, andthis method may aiiord certain constructional advantages. Even with thisarrangement, the adjunction of a ferro-magnetic core 5, preferably ofiron in powder form, r is generally of considerable importance, as foundexperimentally. Qf course, it is necessary to fix From this the lengthand diameter according to each application. a Y

The curve of the magnetizing current as a. function of the time maydepart, if desired, from the sinusoidal shape and in particular mayassume a pointed shape, due to the presence of harmonies of an amplitudewhich, if necessary, is increased artificially by any known means(magnetic saturation, or the like).

Having now particularly described and ascer- 10 tained the nature of thesaid invention and in what manner it is to be performed, we' declarethat what we claim is:

1. A process for the production of ultra-violet and luminous radiationsof adjustable composition, comprising inductively exciting a gaseousatmosphere containing at least one rare gas by exciting an inductivewinding with high frequency current, and increasing the current densityin said atmosphere to. a value. sumciently' high to produce sparkspectra by positioning a magnetic core in said winding and in saidatmosphere.

2. An apparatus for producing ultra-violet and luminous radiationsofailjustable composition by electromagnetically exciting a gaseousatmosphere containing at least one rare gas, comprising an envelopecontaining the gaseous atmosphere, a cylindrical casing penetrating intothe interior of the envelope, the inner end of said casing beingclosedto prevent communication between said envelope and casing, amagnetic core positioned in said casing, and a high frequency excitedcoil positioned in said casing and surrounding said core for setting upa magnetic field to induce current into said gaseous atmosphere.

3. An apparatus for producing ultra-violet and luminous radiations ofadjustable composition by electromagnetically exciting a gaseousatmosphere containing at least one rare gas, comprising an envelopecontaining the gaseous atmosphere, a cylindrical casing penetrating intothe interior of the envelope, the'inner end of said casing being closedto prevent communication be- ,tween said envelope and casing, a magneticcore positioned in said casing, and a high frequency excited coil.positioned exteriorly of said casing and surrounding said core andenvelope for setting up a magnetic field to induce current intosaid-gaseous atmosphere.

4. An apparatus as set forth in claim 2, in which the-core is formed ofstrips of thin iron radially arranged.

5. An apparatus as set forth in claim 3, in

which the core is formed-oi strips of iron radially arranged.

6. "An apparatus as set forth claim 2, in which the core is formed ofwires of very small diameter.

7. An apparatus as set iorth in claim 3, in which the ccreis formed oiwires of very small diameter.

8. An apparatus as set forth in claim 2, in which the core is formed ofmagnetic substances in the form of powder, the grains of which areagglomerated by means or an insulating substance.

9. An apparatus as set forth in claim'3, in which the core is iormed'oimagnetic substances in the form of powder, the grains of which areagglomerated by means of an insulating substance.

10. An apparatus for producing ultra-violet I and luminous radiations ofadjustable composition by electromagnetically-excitinga gaseousatmosphere containing at least one rare gas, comprising an envelopecontaining the gaseous atmosphere, a high frequency exciting winding forinductively exciting the gas in said envelope,

and a magnetic core surrounded by said winding and the gaseousatmosphere for increasing the current density in the gaseous atmosphereto a value required for the production of spark spectra.

JOSEPH BEWOD. ANDRE CLAUDE.

